[PATCH v6 2/4] qapi: Accept bool for OnOffAuto and OnOffSplit

[Akihiko Odaki <akihiko.odaki@daynix.com>]

bool has representations of "on" and "off" different from
OnOffAuto/OnOffSplit:
- The command line syntax accepts on/yes/true/y and off/no/false/n for
  bool but only on and off for OnOffAuto.
- JSON uses true/false for bool but "on" and "off" for
  OnOffAuto/OnOffSplit.

This inconsistency causes some problems:
- Users need to take the underlying type into consideration to determine
  what literal to specify, increasing cognitive loads for human users
  and complexity for programs invoking QEMU.
- Converting an existing bool property to OnOffAuto/OnOffSplit will
  break compatibility.

Fix these problems by accepting bool literals for OnOffAuto/OnOffSplit.
This change is specific to OnOffAuto/OnOffSplit; types added in the
future may be defined as an alternate of bool and enum to avoid the
mentioned problems in the first place.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
 hw/core/qdev-properties.c | 17 ++++++++++++++++-
 scripts/qapi/visit.py     | 24 ++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
index 0b52aad55516099917a4e9b71a920bc3da8a92ec..3462921841db74456284b91374955b6101f03bbc 100644
--- a/hw/core/qdev-properties.c
+++ b/hw/core/qdev-properties.c
@@ -2,6 +2,7 @@
 #include "hw/qdev-properties.h"
 #include "qapi/error.h"
 #include "qapi/qapi-types-misc.h"
+#include "qapi/qapi-visit-common.h"
 #include "qobject/qlist.h"
 #include "qemu/ctype.h"
 #include "qemu/error-report.h"
@@ -493,12 +494,26 @@ const PropertyInfo qdev_prop_string = {
 
 /* --- on/off/auto --- */
 
+static void set_on_off_auto(Object *obj, Visitor *v, const char *name,
+                            void *opaque, Error **errp)
+{
+    Property *prop = opaque;
+    int *ptr = object_field_prop_ptr(obj, prop);
+    OnOffAuto value;
+
+    if (!visit_type_OnOffAuto(v, name, &value, errp)) {
+        return;
+    }
+
+    *ptr = value;
+}
+
 const PropertyInfo qdev_prop_on_off_auto = {
     .name = "OnOffAuto",
     .description = "on/off/auto",
     .enum_table = &OnOffAuto_lookup,
     .get = qdev_propinfo_get_enum,
-    .set = qdev_propinfo_set_enum,
+    .set = set_on_off_auto,
     .set_default_value = qdev_propinfo_set_default_value_enum,
 };
 
diff --git a/scripts/qapi/visit.py b/scripts/qapi/visit.py
index 36e240967b687db10115ba375da3371898b7d95c..5844b64ad6b49a7b88e286dd35ab28b2755282d0 100644
--- a/scripts/qapi/visit.py
+++ b/scripts/qapi/visit.py
@@ -205,6 +205,29 @@ def gen_visit_list(name: str, element_type: QAPISchemaType) -> str:
 
 
 def gen_visit_enum(name: str) -> str:
+    if name in ('OnOffAuto', 'OnOffSplit'):
+        return mcgen('''
+
+bool visit_type_%(c_name)s(Visitor *v, const char *name,
+                 %(c_name)s *obj, Error **errp)
+{
+    bool b;
+    int i;
+
+    if (v->type == VISITOR_INPUT && visit_type_bool(v, name, &b, NULL)) {
+        *obj = b ? %(on)s : %(off)s;
+        return true;
+    }
+
+    b = visit_type_enum(v, name, &i, &%(c_name)s_lookup, errp);
+    *obj = i;
+
+    return b;
+}
+''',
+                     c_name=c_name(name),
+                     on=c_enum_const(name, 'on'), off=c_enum_const(name, 'off'))
+
     return mcgen('''
 
 bool visit_type_%(c_name)s(Visitor *v, const char *name,
@@ -355,6 +378,7 @@ def _begin_user_module(self, name: str) -> None:
         self._genc.preamble_add(mcgen('''
 #include "qemu/osdep.h"
 #include "qapi/error.h"
+#include "qapi/visitor-impl.h"
 #include "%(visit)s.h"
 #include "%(prefix)sqapi-features.h"
 ''',

-- 
2.48.1